Circuit breaker



March 14, 1939.

R. N.. ROWE CIRCUIT BREAKER Filed sept. 28, 1935 In L il 5.........Tf-riff?.

INVENTOR ATTORNEY Patented Mar. 14, 1939 PATENT OFFICE CIRCUIT BREAKER,

Raymond N. Rowe, Plainville, Conn., assignor to The Trumbull ElectricManufacturing Company, Plainville, Conn.,

necticut a corporation of Con- Application September 28, 1935, SerialNo. 42,595

1 Claim.

This invention relates to a heavy duty switch or circuit breaker and hasfor one object to increase the efliciency of such constructions.

Another object is to provide an enclosed arc chamber for a conventionaltype of quick break or snap action switch or circuit breaker.

Another object is to provide a novel type magnetic blow-out device forextinguishing an arc that may be formed on opening the switch.

l0 The invention contemplates the employment of a moving magnetic fieldfor dispersing the arc which tends to form.

Referring to the drawing Fig. 1 is a. side elevation of one embodimentof this invention with parts broken away.

i Fig. 2 is a section of a portion of this device on the line 2--2 ofFig. 1.

Fig. 3 is a section on the line 3--3 of Fig. 2.

The snap action may be of any suitable type. Fig. 4 is a view of a splitwasher.

One electrode or switch contact member in this invention is the shaftIII preferably of nonmagnetic material which is conductive, such ascopper or brass.

The movable switch contact member I I is slidable radially of the shaftI0 and its contact member III' for engagement and disengagement with thesurface of the contact I0. 0n opening the A switch by movement of thecontact member II away from the contact I0', an arc may occur in thespace I2 between the electrodes and under this invention a new type ofmagnetic blow-out is provided for any such arc.

The current passing through this switch is connected at the terminal I3and thence passes through the U shaped thermostatic member, shown indotted lines because such is not a part of this nvention, the current@passing up one leg and down the other of the U shaped thermo- 4`0static element, from whence it passes through the flexible connection orpigtail- I5 secured to one end of the movable switch member Il. Theswitch member II is adapted to slide within a guide bearing I6 formed inthe metal housing surrounding the space in which any arc may occur.

A conductor I1 is spirally wound around one end 'of the shaft I0 and asimilar conductor I8 wound around the other end of 'the same shaft III,these coils being connqected to the same shaft member Ill or inparallel, their opposite ends being connected to the other terminal I9of the switch. The coils being in parallel and wound in the samedirection assist one another in directing the electromagnetic fieldbetween the coils so that the flux is substantially parallel to thecylindrical surface I0.

The metal housing 20, around the contact yIII and the arcing space I2,is likewise of non-magnetic material as is the switch part II. Holes 52I are drilled and tapped in this ring for the purpose of receivingscrews 22 which hold the coils and their housings in position.Contiguous the sides of the ring 2|! are washers 23 of insulatingmaterial which is adapted to withstand the high l0 temperature fromclose proximity of an arc, such insulating washers being of mica or somephenolic condensation product or asbestos or other suitable material.

In order to distribute the flux density sub- 15 stantially uniformlyradially and circumferentially around the contact I0', split washers 2land 25 of magnetic material are located between the coils I1 and I8 andthe insulatingwashers 23. On the opposite side of the coils I1 and I8 20are arranged insulating washers 26 and 21 to safeguard the insulation ofeach of the coils I1 and I8.

Surrounding each of thesecoils is a housing 28 and 29 of molded or otherinsulating material 25 clamped in place by screws 22 as shown in Figs.

2 and 3.

The actuating mechanism for the movable switch part II includes a handlemember 30 pivoted as indicated for moving the spring 3l each 30 side ofits pivot in producing a quick make and break toggle movement for theswitch member I I. On closing the switch II by moving the handle 30 tothe right, the switch member contacts with the stationary contact memberIII'. Should the 35 thermostatic element I4 be bent to the left in Fig.1 and release the lever 32, the springs 33 being heavier than thesprings 3| will cause the switch member II to be snapped open withoutthe handle 30 moving. Manual movement of 40 the-handle 30 to the opencircuit position indicated may then press down the lever 32 and reset itunder the thermostatic latch.

The coils I1 and I8 are of insulated wire wound so that opposite polesare on opposite sides of 45 the arc space, in other words, so that thesplit steel washers 24 and 25 are of opposite polarity.

It has been found that the efliciency of this construction has beenincreased by providing the shaft I0 with a silver alloy contact portionI0' and by either providing the movable contact member II with a sim'larcontact portion or by making the entire body of contact member II of asuitable alloy which is preferably of the silver type.

switch. shown in the drawing, to be capable of breaking approximately5000 amperes at 440 volts with this single pole arrangement illustrated.

I claim:

An electrical switch including a central Bubstantially cylindrical coreof non-magnetic and conductive material, two blow-out coils located oneither end of said core, washers of magnetic core, said coils being inelectrical circuit with said electrodes, whereby the uniform magneticfield and the cyspiral configuration about said core, and substantiallyair-tight housing means enclosing said space between said coils, wherebysaid arc will be more readily extinguished.

RAYMOND N. ROWE.

